Anatomic pathology studies sections and images of human tissue. A pathologist or other professional typically inspects and analyzes a section of human tissue. The inspection may be carried out by marking a sample with a stain, where that stain reveals a visual indicator of diagnostic significance. The same tissue is placed on the slide for viewing under a microscope. The microscope may be manually observed, or may be observed by an automated imaging system.
Capturing areas of the slide sample at high magnification is necessary for examining minute features of the tissue. However, even obtaining a single image of an entire tissue specimen at high magnification e.g. 40×, requires significant computer storage space and lengthy retrieval times.
Sequential slices of tissue, known as serial sections, may include sections of tissues that are obtained by needle biopsies, tissue microarrays, or slices taken from the same block of tissue. These sequential slices are often placed across one or more microscope slides to be viewed serially. A pathologist can observe and/or perform various tests on the array of serial sections.
For example, a pathologist may be interested in whether a particular stain appears in the same region across each tissue sample. Another example is that a pathologist may be interested in the effect that different stains have across the same area of each tissue sample. This system may also be used for three-dimensional image reconstruction of a block of tissue.
Precision is often an issue. One common way of preparing serial sections slides involves embedding tissue in wax, sectioning it at specified thicknesses e.g. 4 microns, and/or allowing the sections to float on a water bath. Techniques are used to keep the tissue in the same general location across each slide. However, errors may cause the tissue section to be inconsistently located—e.g., located in a different location on the slide, rotated or flipped, stretched, or having different size cut. The tissue may also be torn or have a distorted shape.
An area of significance on one slide of a serial section of slides, may be located in a different area on a different slide.